Funnel most proxy creation through GrProxyProvider

This is to provide a choke point for DDL to create Lazy Proxies.

Change-Id: If178da13bc6447b31b7601810236d34502d9efbd
Reviewed-on: https://skia-review.googlesource.com/93303
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/GrTextureRenderTargetProxy.h b/src/gpu/GrTextureRenderTargetProxy.h
index 739f797..63cc487 100644
--- a/src/gpu/GrTextureRenderTargetProxy.h
+++ b/src/gpu/GrTextureRenderTargetProxy.h
@@ -23,7 +23,9 @@
 // the uniqueID of the RenderTarget/Texture it represents!
 class GrTextureRenderTargetProxy : public GrTextureProxy, public GrRenderTargetProxy {
 private:
+    // DDL TODO: rm the GrSurfaceProxy friending
     friend class GrSurfaceProxy; // for ctors
+    friend class GrProxyProvider; // for ctors
 
     // Deferred version
     GrTextureRenderTargetProxy(const GrCaps&, const GrSurfaceDesc&,